Method and apparatus for treating paper stock



E. COWLES June '13, 1944.

METHOD AND APPARATUS FOR TREATING PAPER STOCK 3 Sheets-Sheet 1 FiledJan. 15, 1940 I NVENTR A fb/g ATTORNEY June 131944. E. cowLl-:s2,351,492

METHOD AND APPARATUS FOR TREATING PAPER STOCK Filed Jan. 15, 1940 5Sheets-Sheet 2 Y: IQVENTOQ ATTORNEY June 13, 1944. E, cowLl-:sl2,351,492

METHOD AND APPARATUS FOR TREATING PAPER STOCK Filed Jan. 15, 1940 3Sheets-Sheet 3 I Il IH 78 y l ,4 lll* f5. /7 'O16 K 0) 2 lNVENTORPatented June13, 1944 METHOD AND mensrusron 'mirarme Persa s'roox EdwinCowles, Cayuga, N. Y., assigner toa.The

Cowles Company, Princeton, N. J.; a corporation oi' New Jersey fApplication January 15, 1949,

\ Serial No; 311,107 Y' ..13 "lot 92-26) This invention relates tomethods and apparatus for treatingv paper stock, and pertains moreparticularly to method and apparatus for deilbering, rening andotherwise preparing paper stock for use on paper making machines.

In a prior patent, No. 1,883,597 issued October 18, `1932, I'described amethod of treating paper stock in which the stock is contained in a vat,and is circulated by a pump which withdraws stock from the vat andreturns it thereto, the returned stock being discharged into the vat' athigh velocity through submerged nozzles. The high velocity jetsdischarged by the nozzles exercise a deiibering and reilning effect onthe stock due to moving through the relatively stationary body of stockin the vat.

Subsequently, in Patent No. 2,219,571, issued October 29, 1940, Idescribed a different form of apparatus utilizing the principle of myaforementioned patent. In said patent, however, instead of withdrawingstock from the vat and returning it to the vat vthrough nozzles, Iprovide a rotary impeller which is submerged in the said impeller isprovided with open grooves so the tearing effect oi the high velocityjets vat, whichl given aperture area may be increased by changing theshape of the aperture. Thus, a nozzle havsheet, such as a relativelythin annular disk. `In

the preferred embodiment illustrated this is accomplished by mounting a.multiplicity o1' vanes A on the surface of an open impeller disk. adJa-idesigned as to discharge high velocity jets from the rim of theimpeller, which saidjets have the same reiining and deiibering effect asthe jets discharged from the nozzles in the aforementioned patent.

According to the present to utilize the principleof reilning anddebering by discharging stock at high velocity through a surroundingbody of relatively stationary stock, but it is an object of the presentinvention to ininvention continue i crease the elciency of the renlngand debering action.

At the outset, it is necessary to understand that in utilizing theprinciple of high velocity discharge, the desired refining and deberlngaction takes place along the surfaces of the body of stock which ismoving at high velocity, i. e. along the areas where there is a greatdiil'erential in velocity. Thus, ii the stock is discharged from anozzle having a circular aperture, the refining and deiibering actionoccurs along a cylindrical or conical surface, but the stock within thecylinder or cone receives little or no rening or deilbering effect,since the stock within the cylinder or cone moves along, until itsenergy is spent, without being subjected to the tearing eiect whichoccurs at the surface of the cylinder or cone.

It will also be understood that the surface area of a jet dischargedfrom a circular nozzle of any cent the rim thereof, said vanes beingrelatively low and being closely spaced, so that stock is discharged athigh velocity around the entire periphery of the impeller in the form ofa relatively thin annular disk. The slu'face area of the discharged diskoi stock is very great and consequently the rening and deilbering eectis very rapid and eilicient.

According to the present invention, I also combine the purely hydraulicrefining and debering action described above with what mayv be called amechanical refining and deilbering action. For this purpose, I providethe impeller vaneswith knife edges, inclined, as hereinafter explained,to engage the ilbers so that they slide or roll along said edge andthereby receive a mechanical rubbing action. This action, taking placeat a point where the stock is being accelerl ated by the vanes fordischarge at high velocity is particularly effective, and combined withthe hydraulic action previously described provides an extremelyeilicient deilbering and rening action.

Other objects and advantages of the invention will appear hereinafter.

A preferred embodiment o! the invention selected for purposes ofillustration is shown in the accompanying drawings, in which,

Figure 1 is a vertical sectional view.

Figure 21s a plan view of a portion oi the imer. Figure 3 is a sideelevation of one of the inner impeller vanes.

Figure 4 is a top plan view of one ofthe outer impeller vanes. A

Figure 5 is a side elevation of the same. Figure 6 is a vertical sectionthrough the impeller.

provided, preferably cylindrical in shape, which said tank may, ifdesired, have its side walls lined with tile 2. The bottom of the tankis provided with a sunken chamber il, and the space between said chamberand the cylindrical side wall of the tank may be filled with concrete 4to provide a sloping surface as illustrated in Figure 1. Such a slopingsurface directs the stockdischarged from the impeller, as hereinafterexplained, upwardly along the side walls of the tank and as sists inmaintaining circulation in the stock contained in the tank as indicatedby arrows in Figure l. If desired, fixed directional vanes 5 may beembedded in the concrete to direct the stock which ls discharged fromthe impeller inan upward direction and to restrain to some extent thecirculation in a horizontal plane.

An impeller, in the form of a disk i0, is mountedin the chamber 3,andmay be rotated in any suitable manner, as by pulley ii, driven bymotor I2, operating through-suitable reduction gears (not shown) mountedin the housing i3.

The impeller disk is provided with a multiplicity of impeller vanes I4mounted adjacent the rim of the disk, said vanes projecting ,upwardlyfrom the upper lsuri'ace of the disk. l The said vvanes may be securedto the disk in any suitable manner, but in the embodiment illustrated,the 4vsuzies are secured, as by welding, to a ring I5 which is set intoa groove IG formed in the disk, which said ring is held in place byscrews i1. Thus, the impeller is of the open type, being distinguishedfrom the closed type impellers by the absence of any enclosures, hoods,shrouds, passages or the like which are commonly used to increase theefdciency of impellers employed for pumping or circulating purposes, butwhich are `wholly unsuited for deflbering paper stock.

In order to avoid stapling of stock on the vanes Il, the advancing facei of each vane is inclined to the surface of the disk, and in caseswhere the mechanical action referred to is desired, 'the face is slottedto receive a blade I 9 having a knife -edge 20. The knife edge is alsoinclined to the surfaceV of the disk at an angle such that the bersengaged thereby roll and slide along the edge. The angle of inclinationshould preferably not exceed 30 and is preferably somewhat less, as forexample, the angle illustrated in the drawings is approximately 18. Thelower edge .of the blade is provided with a hook portion 2| whichengages a mating hook portion in the slot to hold the blade firmly inposition, but to allow easy removal for replacement. Preferably thetrailing end of the blade I9 extends somewhat beyond the end of theinclined face of the vane and terminates in a point 23'which has apicking action on large pieces of solid material which may be introducedinto the tank. A multiplicity of such edges and points, actingsuccessively on a large piece of solid material, operate in the mannerof a saw to rapidly reduce such pieces to smaller size.

'I'he height of the varies above the surface of the disk is smallrelative to the diameter of the disk at the circumference whichintersects the mid point of said vanes, and should not exceed a ratio of1 to 30. For example, using a disk having a diameter of the height ofthe vanes should not exceed 2", and should preferably be about 1%". sothat the disk of stock discharged from` the impeller will be relativelythin.

The impeller should be rotated at a rate sufilcient to discharge thestock at the rim of the locities, as for example,

`have sh Y 2,851,492 Referring to the drawings, a vat or tank i isimpeller at a velocity of at least 1000 ft. per minute and in some casesat considerably higher vebetween 1,000 and 2,000 ft. per minute, theparticular velocity selected in excess of 1000 ft. per minute dependingon the toughness of the stock being treated. For purposes of this high vlocities specification,l therefore, the term ocity" is defined ascomprehending veexcess of 1000 ft. per minute, for tests wn that whilesome deflbering action may be oduced at lower velocities, it is notpossible to produce completely debered stock within the limits ofpractical operation. At lower velocities it has been found thatdeiibering proceeds with reasonable rapidity until the undeflberedpieces of stock reach a certain size, after which the rate of deberingis rapidly reduced or deilbering action may cease entirely. Even long econtinued treatment often fails to produce complete deilberization.Using high velocities, as dened herein, however, rapidly to completion.The mechanical action of the blades i9 has been found to be particularlyeffective. not only in aiding vthe hydraulic action ,in deilberingundebered stock, but also in refining the debered stock. In thisconnection, it will be notedthat since the blades are located on thevanes, at a -point where the stock is being accelerated, and since theblades are inclined to the surface of the impeller disk, the 'bers whichare engaged thereby are subjected to a severe mechanical rubbing actionboth against the blades and against adjacent fibers. The effect producedon the fibers in this manner is very useful, in that after debering iscomplete, less subsequent treatment is required to prepare the stock foruse on paper machines.

It is important to maintain proper circulation oi the stock at all timesin order that all portions oi' the stock may be repeatedly subjected tothe action of the impeller. The preferred type of circulation is thatwhich is in the nature of a vortex or whirlpool comprising circulationin both horizontal and vertical planes. It has previously been statedthat the sloping sections 4 of the bottom ofthe tank contribute to thisresult in directing the stock discharged from the impeller upwardlyalong the sides of the tank, and it-has also been pointed out thatexcessive circulation in the horizontal plane may be restrained by fixeddirectional vanes 5.

Anotherl contributing feature in this connection is the relativediameters of the impeller and the tank, for it has been found that inorder to maintain proper circulation. the diameter of the impellershould be greater than one fourth and less than one half the diameter ofthe tank.

Still another contributing feature to the maintenance of propercirculation is the supplementary vanes 25 which are also mounted on theupper face of the impeller disk between the vanes Il and the center ofrotation of the impeller. The advancing face 20 of the vanes 25 may beinclined to the face of the disk, as shown, to prevent pieces of stockfrom stapling thereon. The said vanes 25 initially accelerate the stockat the center of the impeller and move it toward the vanes Il whichadditionally accelerate it and discharge it in disk form as previouslydescribed. Since the vanes 25 continually move stock away from thecenter oi' the impeller, thus drawing stock down centrally from the-topof the tank, they assist greatly in maintaining the Vertical.circulation which has been found so deiihering action proceeds highlyuseful in the operation of this apparatus. When the consistency of thestock ir low, as at the beginning of a batch operation, the vorticalcavity may extend all the way down-to the impeller, so that the impellermay be seen from the top of the tank."V As the consistency increases thedepth of the cavity may decrease, but the vortical circulationcontinues. so that the undebered portions of the stock, frequently inpieces of large sizewhich otherwise tend to float on the surface, aredrawn down into the vortex and are immediately subjected to thedeflbering action of the impeller.

This feature of the invention permits a method of operation hithertounknown in the preparation of paper stock. In using the ordinary breakerbeater. for example, it is necessary to feed in the solid materialslowly in small batches allowing each batch to be partially deberedbefore introducing additional batches. Otherwise the machine becomesclogged or jammed and must be shut down. Considerable time is thusconsumed in merely charging the machine, after which additional treatingtime is required. With the'present apparatus, however the entire chargeof solid material may be irftroduced at one time at the beginning oi'the operation when the consistencyis at its lowest point and thevortical action is at its maximum effectiveness. Thus. at the beginningof an operation, the required amount of water is introduced into thetank. and the required amount of solid material is introduced to producewhatever stock consistency is desired in the finished batch, as forexample, from 3% to 10% consistencv. As the operation proceeds, theaction of the vortex is relied` upon entirely tosubmerge the solidmaterial and bring it linto the zone of action of the impeller.

The machine particularly illustrated and described herein is intendedfor batch operation, but it will be understood that it may be combinedwith devices such as illustrated in my copending application Serial No.267,804 which permit continuous withdrawal of debered material 4 fromthe chamber 3, and consequently, continuous operation of the machine. Inthe present machine. the chamber 3 which surrounds the impeller isprovided with two drain pipes 28 and 28', controlled by valves 29 and29' which may, o

if desired. be operated hydraulically by pistons 30 and 30'. Fresh watersupply pipes 3| and 3i' are provided for iiushing out the chamber 3after the contents of the tank have been discharged.

It will be understood that while the invention has been described hereinwith particular reference to the treatment of paper stock, the apparatusdescribed and claimed herein may also be employed to advantage for manyother purposes and uses. Thus, such apparatus may be used for thegeneral purpose of disseminating, dspersing and maintaining insuspension divisible insoluble solids, and for breaking up and puttinginto solution solids which are soluble.

It will be understood that the invention may be variously modified andembodied within the scope of the subioined claims.

I claim as my invention:

1. The method of pulping paper stock in batches which comprisesintroducing the required amount of water into a tank, introducing theentire charge of fibrous, material required to produce the desired batchconsistency into said tank at one time, and maintaining a vorticalcirculation with a hollow core in said tank whereby iloating solidmaterial is submerged by the action of the vortex.

2. The method of pulping paper stock in batches which comprisesintroducing the required amount of water into a tank, introducing acharge of solid fibrous material into said tank at one time, said chargebeing sufcient to produce a stock consistency in excess of 3% in thefinished stock, and maintaining a v'ortical circulations with a hollowcore in said tank whereby floating solid material is submerged by theaction of the vortex.

3. The method of pulping paper stock in batches which comprisesintroducing the required amount of water into a tank, introducing theentire charge of brous material required to produce the desired batchconsistency into said tank at one time, maintaining a vorticalcirculation with a hollow core in said tank whereby floating solidmaterial is submerged by the action of the vortex, and subjecting thesolid iibrous material to debering action at the bottpm of said vortex.

4. The method of pulping paper stock which comprises, creating avortical circulation with a hollow core in a tank by means of a rotaryimpeller submerged in the tank with its axis beneath the core of thevortex, said impeller discharging stock outwardly in a directionsubstantially at right angles to the axis of rotation thereof andfeeding and submerging light brous material through said core directlyto said impeller. r

5. Apparatus of the character described, comprising, in combination, atank containing stock -to be treated, an impeller disk mounted forrotation in said tank, said impeller having a plurality of vanes offsetfrom its surface and freely exposed to the stock in said tank, saidvanes being located substantiallyv at the periphery of said disk, theratio of the height of said vanes to the diameter of the disk being lessthan one to thirty, whereby when said impeller disk is rotated at highspeed, a thin disk of high velocity stock is discharged in a directionsubstantially at right angles to the axis of rotation of said disk.

6. Apparatus of the character described, comprising, in combination, atank containing stock t0 be treated, an impeller disk mounted forrotation in said tank, said impeller having a plurality of vanes offsetfrom its surface and freely exposed to the stock in said tank, the ratioof the height of said vanes to the diameter of said disk at thecircumference which intersects the mid point of said vanes being lessthan one to thirty, whereby when saidv impeller disk is rotated at highspeed, a thin disk of high velocity stock is discharged in a directionsubstantially at right angles to the axis of rotation of said disk.

'7. Apparatus of the character described, com prising, in combination, atank containing stock to be treated, an impeller disk mounted forrotation in said tank, said impeller having a plurality of varies offsetfrom its surface and freely exposed to the stock in said tank, saidvanes having impelling surfaces substantially perpendicular to thesurface of said disk but inclined to a radius of the disk passingtherethrough, the ratio of the height of said varies to the diameter ofsaid disk at the circumference Where the Vmid point of said vanes islocated being less than one to thirty, whereby when said impeller diskis rotated at high speed, a thin disk of high velocity stock isdischarged in a direction substantially at right angles to the axis ofrotation of said disk.

8. Apparatus of the character described, com.

prising, in combination, a tank containing stock to be treated, animpeller disk molmted for rotation in said tank, said impeller diskhaving a plurality ot vanes offset from its surface and disk, andadditional means carried by said impeller disk for assisting inestablishing a downward ilow of stock toward the center of saidimpeller.

9. Apparatus of the character described, comprising, in combination, atank containing stock to be treated, an impeller disk mounted forrotation in said tank, said impeller disk having a plurality of vanesoifset from its surface and freely exposed to the stock in the tank, theratio of the height of said vanes to the diameter of said disk at thecircumference where the mid point of said vanes is located being lessthan one to thirty, whereby when said impeller disk is rotated at highspeed, a thin disk of high velocity stock is discharged in a directionsubstantially at right angles to the axis of rotation ofsaid disk, saidimpeller disk also 'being provided with additional vanes locatedinwardly of saidilrst named vanes, said additional vanes being adaptedto move stock outwardly toward said nrst named vanes.

10. Apparatus of the character described.'

comprising, in combination, a tank containing stock to be treated, animpeller disk mounted for rotation on a vertical axis in said tank, saidimpeller disk having a plurality of vanes oilset from its surface andfreely exposed to the stock in the tank, said vanes being relativelyshallow and located substantially at the periphery of the disk, theratio of the height of said'vanes to the diameter of the disk being lessthan one' to thirty. whereby when said impeller disk is rotated at highspeed a thin disk of high velocity stock is discharged in a direction atright angles to the axis of rotation of said disk, and a vorticalcirculation is induced with the axis of the vortical circulationcoinciding substantially with the axis of rotation of the impeller.

-11. Apparatus of the character described, comprising, in combination, atank containing stock to be treated, an impeller disk in the bottom 'ofsaid tank and mounted for rotation on a vertical axis, said disk beingprovided with a plurality of vanes upon its upper surface and freelyexposed on the upper side to the stock in said tank, said vanes beingrelatively shallow and located substantially at the periphery of thedisk, the ratio of the height of said vanes to the diameter of the diskbeing less than one to thirty, 'whereby when said impeller disk isrotated at high speed a thin disk of high velocity stock is dischargedin a direction at right angles to the axis of rotation of said disk, anda vortical circulation is induced with a hollow core of sumcient depthto feed material from the sur-l face of the stock to the central uppersurface of said impeller.

12. Apparatus of the character described. comprising, in combination, atank, an impeller disk in the bottom o f said tank and mounted forrotation on a vertical axis, said disk being provided with inner andouter sets of vanes upo'n its upper surface and freely exposed on theupper side to the stock in said tank, said outer vanes being relativelyshallow and located substantially at the periphery of the disk, theratio of the height o! said vanes to the diameter of the disk being lessthan one to thirty, and said inner vanes being adapted to move stockoutwardly toward said outer vanes. said vanes being so constructed andarranged that when said impeller disk is rotated at high speed a thindisk of high velocity stock is discharged in a direction at right anglesto the axis of rotation of said disk, and a vortical circulation isinduced with a hollow core of sumcient depth to feed ma-v teal from thesurface of the stock to the central upper surface of said impeller.

13. The method of pulping paper stock which comprises. discharging anannular disk of' stock in a substantially horizontal direction through asurrounding body of stock, maintaining a vortical circulation of thebody of stock above said disk of stock with a hollow core leadingdownward from the surface of the stock to the center of said dischargeddisk of stock, so that floatingfibrous material may be submerged by theaction of said vortex, and subjecting the same at the bottom of thevortex to the deibering action of the discharged disk of stock.

EDWIN COWLES.

Disclaimer 2,351,492.-Edwin Cowles, Cayu a., N. Y. METHOD AND APPARATUSFon TREATINQ PAPER S'rocx. Patent ated June 13, 1944. Disclaimer filedNov. 16, 1949, by the assignee, The OowleaCompany. Hereb enters thisdisclaimer to claims 1, 2, 3, 4, and 13 of said patent,

[ fcial Gazette December 20, 1949.]

